Methods of identifying and replacing implanted heart valves

ABSTRACT

A prosthetic heart valve configured to replace a native heart valve and for post-implant expansion and having a valve-type indicator thereon visible from outside the body post-implant. The indicator communicates information about the valve, such as the size or orifice diameter of the valve, and/or that the valve has the capacity for post-implant expansion. The indicator can be an alphanumeric symbol or other symbol or combination of symbols that represent information about the characteristics of the valve such as the valve size. The capacity for post-implant expansion facilitates a valve-in-valve procedure, where the valve-type indicator conveys information to the surgeon about whether the implanted valve is suitable for the procedure and informs the choice of the secondary valve.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.29/579,402, filed Sep. 29, 2016, which is a continuation-in-part of U.S.patent application Ser. No. 14/745,287, filed Jun. 19, 2015, now U.S.Pat. No. 9,504,566, which claims the benefit of U.S. Patent ApplicationNo. 62/015,290, filed Jun. 20, 2014, the entire contents all of whichare expressly incorporated by reference herein.

TECHNICAL FIELD

This disclosure relates to a surgical heart valve for heart valvereplacement and, more particularly, to surgical heart valves havingindicators visible from outside the body post-implant.

BACKGROUND

The heart is a hollow muscular organ having four pumping chambers andfour heart valves: aortic, mitral (or bicuspid), tricuspid, andpulmonary. Heart valves are comprised of a dense fibrous ring known asthe annulus, and leaflets or cusps attached to the annulus.

Heart valve disease is a widespread condition in which one or more ofthe valves of the heart fails to function properly. Diseased heartvalves may be categorized as either stenotic, wherein the valve does notopen sufficiently to allow adequate forward flow of blood through thevalve, and/or incompetent, wherein the valve does not close completely,causing excessive backward flow of blood through the valve when thevalve is closed. Valve disease can be severely debilitating and evenfatal if left untreated. Various surgical techniques may be used toreplace or repair a diseased or damaged valve. In a traditional valvereplacement operation, the damaged leaflets are typically excised andthe annulus sculpted to receive a replacement prosthetic valve.

A surgical prosthetic heart valve typically comprises a supportstructure (such as a frame, ring and/or stent) with a valve assemblydeployed therein. The support structure is often rigid, and can beformed of various biocompatible materials, including metals, plastics,ceramics, etc. Two primary types of heart valve replacements orprostheses are known. One is a mechanical-type heart valve that uses aball and cage arrangement or a pivoting mechanical closure supported bya base structure to provide unidirectional blood flow, such as shown inU.S. Pat. No. 6,143,025 to Stobie, et al. and U.S. Pat. No. 6,719,790 toBrendzel, et al., the entire disclosures of which are hereby expresslyincorporated by reference. The other is a tissue-type or “bioprosthetic”valve having flexible leaflets supported by a base structure andprojecting into the flow stream that function much like those of anatural human heart valve and imitate their natural flexing action tocoapt against each other and ensure one-way blood flow.

In tissue-type valves, a whole xenograft valve (e.g., porcine) or aplurality of xenograft leaflets (e.g., bovine pericardium) can providefluid occluding surfaces. Synthetic leaflets have been proposed, andthus the term “flexible leaflet valve” refers to both natural andartificial “tissue-type” valves. In a typical tissue-type valve, two ormore flexible leaflets are mounted within a peripheral support structurethat usually includes posts or commissures extending in the outflowdirection to mimic natural fibrous commissures in the native annulus.The metallic or polymeric “support frame,” sometimes called a “wireform”or “stent,” has a plurality (typically three) of large radius cuspssupporting the cusp region of the flexible leaflets (e.g., either awhole xenograft valve or three separate leaflets). The ends of each pairof adjacent cusps converge somewhat asymptotically to form upstandingcommissures that terminate in tips, each extending in the oppositedirection as the arcuate cusps and having a relatively smaller radius.Components of the valve are usually assembled with one or morebiocompatible fabric (e.g., Dacron® polyethylene terephthalate (PET))coverings, and a fabric-covered sewing ring is provided on the inflowend of the peripheral support structure.

One example of the construction of a flexible leaflet valve is seen inU.S. Pat. No. 6,585,766 to Huynh, et al. (issued Jul. 1, 2003), in whichthe exploded view of FIG. 1 thereof illustrates a fabric-coveredwireform 54 and a fabric-covered support stent 56 on either side of aleaflet subassembly 52. The contents of U.S. Pat. No. 6,585,766 arehereby incorporated by reference in their entirety. Other examples ofvalve and related assemblies/systems are found in U.S. Pat. No.4,084,268, which issued Apr. 18, 1978; U.S. Pat. No. 7,137,184, whichissued on Nov. 21, 2006; U.S. Pat. No. 8,308,798, filed Dec. 10, 2009;U.S. Pat. No. 8,348,998, filed Jun. 23, 2010; and U.S. PatentPublication No. 2012/0065729, filed Jun. 23, 2011; the entire contentsof each of which are hereby incorporated by reference in their entirety.

Sometimes the need for complete valve replacement may arise after apatient has already had an earlier valve replacement for the same valve.For example, a prosthetic heart valve that was successfully implanted toreplace a native valve may itself suffer damage and/or wear and tearmany years after initially being implanted. Implanting the prostheticheart valve directly within a previously-implanted prosthetic heartvalve may be impractical, in part because the new prosthetic heart valve(including the support structure and valve assembly) will have to residewithin the annulus of the previously-implanted heart valve, andtraditional prosthetic heart valves may not be configured to easilyreceive such a valve-within-a-valve implantation in a manner whichprovides secure seating for the new valve while also having a largeenough annulus within the new valve to support proper blood flowtherethrough.

Some attention has been paid to the problem of implanting a new valvewithin an old valve. In particular, the following disclose varioussolutions for valve-in-valve systems: U.S. Patent ApplicationPublication No. 2010/0076548 A1 to Konno, filed Sep. 19, 2008; and U.S.Pat. No. 8,613,765 to Bonhoeffer, filed Jul. 7, 2011.

Despite certain advances in the valve-in-valve area, there remains aneed to quickly identify physical characteristics of a previouslyimplanted heart valve, including whether a previously implanted surgicalvalve is suitable for a valve-in-valve procedure.

SUMMARY

The present application solves a number of problems related toidentification of prosthetic heart valves post-implant. The heart valveshave an indicator thereon visible from outside the body by an externalimager, post-implant. The indicator communicates the size or orificediameter of the surgical valve, and may also show that the valve has thecapacity for post-implant expansion. It can also communicate otherinformation, such as any combination of the manufacturer and/or model ofthe valve, the type of bioprosthetic tissue or other material used tomake the leaflets, and the valve's compatibility with other types ofvalves. The indicator may be an alphanumeric symbol and/or other symbolor symbols that represent, for example, the valve size number and/orother characteristic.

The present application discloses specific modifications to existingsurgical valves that enable manufacturers to rapidly produce a valvewhich accommodates valve-in-valve (ViV) procedures. Specifically, someembodiments disclosed in the present application include retrofitting ormodifying components within existing types of surgical valves to enablepost-implant expansion.

In one embodiment of the present application, a prosthetic heart valvecomprises an internal support frame defining a flow orifice therethroughand wherein the internal support frame is adapted for post-implantexpansion. A plurality of flexible leaflets attaches to the supportframe so as to extend across the flow orifice and come together withinthe orifice and provide one-way flow therethrough. The prosthetic heartvalve further includes a valve-type indicator that provides informationabout a characteristic of the heart valve and is visible using anexternal imager. The valve-type indicator may signify the capability ofthe support frame for post-implant expansion of the orifice.

The prosthetic heart valve preferably has a labeled valve size, and thevalve-type indicator comprises a valve-size indicator that denotes thelabeled valve size and is visible or readable using an external imager.For example, the valve-size indicator comprises a numerical value thatequals the labeled valve size in millimeters. In one embodiment, theinternal support frame comprises a structural component that shows up asa positive image on the external imager, and the valve-type indicator isformed by one or more voids integrated into the structural componentthat show up as negative images on the external imager. For instance,the structural component of the internal support frame may be agenerally tubular band that is adapted for post-implant expansion. Insome embodiments, the valve-type indicator is integrated into astructural component to provide a positive image, for example as part ofa band, stent, and/or wireform.

In another embodiment, the valve-type indicator comprises an indicatorelement that shows up as a positive image on the external imager mountedto a structural component of the prosthetic heart valve that is notclearly visible to the external imager so that the valve-size indicatorshows in contrast to the structural component on the external imager.For example, the structural component comprises a soft sealing ringsurrounding an inflow end of the heart valve, and the indicator elementis mounted to the sealing ring.

In one aspect, the prosthetic heart valve further includes an expandabletubular frame attached to an inflow end of the internal support frame onwhich the valve-size indicator is located. In such a configuration, theexpandable tubular frame may have a series of circumferential and axialstruts, wherein an upper strut is shaped with peaks and valleys aroundits periphery, and the valve-type indicator is integrated into the frameas a tag below the upper strut and along one of the axial struts. Theexpandable tubular frame is desirably metallic and is formed by lasercutting with the tag being the same material as the frame and formedduring the laser cutting process.

In another embodiment, a prosthetic heart valve disclosed hereincomprises an internal support frame defining a flow orificetherethrough, and a plurality of cusps that curve toward the inflow endseparated by commissures. The support frame comprising an annularelement disposed at an inflow end of the support frame that undulates soas to have peaks and valleys, with the peaks corresponding to thecommissures of the support frame. A plurality of flexible leafletsattach to the support frame and extend across the flow orifice so as tocome together within the orifice and ensure one-way flow therethrough,each of the leaflets attaching at a peripheral edge along the cusps andcommissures of the support frame. An indicator is located on the annularelement, for example, on at least one of the peaks or on at least one ofthe valleys of the annular element, that denotes a valve type and isvisible or readable using an external imager.

In one form, the annular element includes a single expandable segmentformed by overlapping free ends located at one of the cusps of thesupport frame. Preferably, there are identical indicators provided oneach of the peaks in the middle of each valley around the annularelement. The prosthetic heart valve has a labeled valve size, and thevalve-type indicator may comprise a numerical value that equals, or anon-numeric symbol representative of, the labeled valve size inmillimeters. The annular element desirably comprises a generally tubularmetallic band that shows up as a positive image on the external imager,and the valve-type indicator is formed by one or more voids integratedinto the band which show up as negative or positive images on theexternal imager.

The heart valve may further include an expandable tubular frame attachedto an inflow end of the internal support frame on which a secondvalve-type indicator is located. The expandable tubular frame maycomprise a series of circumferential and axial struts, wherein an upperstrut is shaped with peaks and valleys around its periphery, and thevalve-type indicator is integrated into the frame as a tag below theupper strut and along one of the axial struts.

Some embodiments provide a prosthetic heart valve, comprising: aninternal support frame defining a flow orifice therethrough, theinternal support frame is adapted for post-implant expansion; aplurality of flexible leaflets attached to the support frame andextending across the flow orifice and coming together within the orificeto define one-way flow therethrough; and a valve-type indicator thatprovides information about a characteristic of the heart valve, thevalve-type indicator readable using an external imager.

Some embodiments provide a prosthetic heart valve, comprising: aninternal support frame defining a flow orifice therethrough, theinternal support frame defining a plurality of cusps that curve towardthe inflow end separated by commissures, the support frame comprising anannular element disposed at an inflow end of the support frame thatundulates so as to have peaks and valleys, with the peaks correspondingto the commissures of the support frame; a plurality of flexibleleaflets attached to the support frame and extending across the floworifice and coming together within the orifice to ensure one-way flowtherethrough, each of the leaflets attaching at a peripheral edge alongthe cusps and commissures of the support frame; and an indicatorcomprising at least one feature in annular element at least a portion ofthe indicator having a radiopacity different from the radiopacity of theannular element, the indicator indicating a valve type and visible usingan external imager. At least a portion of the annular element can beradiopaque, with the indicator including at least one opening extendingthrough the at least one radiopaque portion of the annular element.

Some embodiments provide a method for replacing a prosthetic valve inneed thereof, the method comprising: reading a valve-type indicator of afirst prosthetic valve, selecting a second prosthetic valve based on theinformation read, and deploying the second prosthetic valve in the firstprosthetic valve. Optionally, the method includes expanding a diameterof the first prosthetic valve prior to, contemporaneously with, orsimultaneously with deploying the second prosthetic valve.

Other features and advantages of the present invention will becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawings which illustrate, by way of example, theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1E are perspective and cutaway views of an exemplary surgicalprosthetic heart valve of the present application having innerstructural bands adapted for post-implant expansion and havingvalve-size indicators on an internal component visible from outside thebody;

FIG. 2 is a side elevational view of an exemplary surgical prostheticheart valve of the present application;

FIG. 3 is a schematic view of an image of a prosthetic heart valve ofthe prior art as seen using an X-ray or other imager from outside thebody in the same orientation as FIG. 2;

FIG. 4 is a schematic image similar to that of FIG. 3 of a prostheticheart valve of the present application having valve-size indicators onan internal frame component that are visible from outside the body usingan X-ray or other imager;

FIGS. 5A-5D are elevational views of different outer support bands foruse in the valve of FIGS. 1A-1E with valve-size indicators thereon invarious locations, the bands having overlapping free ends held togetherby a frictional sleeve to enable post-implant expansion;

FIG. 6A is an elevational view of an alternative outer support bandhaving a symbolic valve-size indicator thereon at one of the cusps ofthe band, and FIG. 6B is a key chart for decoding the meaning of thesymbolic valve-size indicator;

FIG. 7 is an elevational view of a still further outer support bandhaving a plurality of holes formed around its circumference whose numberequals the valve size in millimeters;

FIG. 8A is an elevational view of another outer support band having asymbolic valve-size indicator thereon at one of the commissures, andFIG. 8B is a key chart for decoding the meaning of the symbolicvalve-size indicator;

FIG. 9A is another outer support band having a symbolic valve-sizeindicator thereon at one of the commissures, and FIG. 9B is a key chartfor decoding the meaning of the symbolic valve-size indicator;

FIG. 10 is an elevational view of a still further outer support bandhaving a plurality of holes provided on one of the cusps whose numbersymbolizes a particular valve size;

FIGS. 11A and 11B show support bands each having a single geometricsymbol formed in at least one of the cusps that symbolizes a particularvalve size;

FIG. 12 is a still further outer support band having a radiopaquecoating thereon in a pattern that symbolizes a particular valve size;

FIGS. 13A-13C are perspective views of a further prosthetic heart valvesupport band indicated for post-implant expansion and having overlappingfree ends held together by a frictional sleeve, and FIG. 13D shows theexpansion of the overlapping free ends;

FIG. 14A is a perspective view of an inner core member of an exemplarysewing ring showing strips of radiopaque material exploded therefromthey can be incorporated into the sewing ring to indicate valve size,and FIG. 14B is a schematic top view as seen using an X-ray or otherimager from outside the body of the valve having the radiopaque stripsas indicated in FIG. 14A;

FIGS. 15A-15C are perspective and elevational views, some cutaway andphantom, of an exemplary prosthetic heart valve of the presentapplication having an expandable lower frame with valve-size indicatorsthereon; and

FIG. 16 is a perspective view of the lower frame with valve-sizeindicators of FIGS. 15A-15C.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The prosthetic heart valves described herein each include an internal(meaning incorporated into the valve itself as opposed to being asupplemental element) stent or frame that is generally tubular in shapeand defines a flow orifice area through which blood flows from an inflowend to an outflow end. Alternatively, the shape of the internal stentcan be oval, elliptical, irregular, or any other desired shape. Thevalves preferably include flexible leaflets that selectively allow forfluid flow therethrough. Thus, the flow orifice area is alternativelyopen and closed via movement of leaflets. The heart valves may alsoinclude an outer or peripheral sewing or sealing ring formed of soft,suture-permeable material, which is typically used as an anchor tosecure the valve to a native annulus, but can also be primarily forsealing against paravalvular leaking.

As referred to herein, the prosthetic heart valves used in accordancewith the devices and methods of the invention may include a wide varietyof different configurations, such as a prosthetic heart valve having oneor more bioprosthetic tissue leaflets (e.g., bovine or porcine), asynthetic heart valve having polymeric leaflets, and in general any thatare configured for replacing a native or previously implanted prostheticheart valve. The prosthetic heart valves described herein are typicallyused for replacement of aortic, mitral, tricuspid, or pulmonic valves,but may also be used as a venous valve. These replacement prostheticheart valves can also be employed to functionally replace stentlessbioprosthetic heart valves.

In a preferred embodiment, internal valve stents or support framesdisclosed herein have “expandable segments” that enable post-implantexpansion. This can occur from the expandable segment rupturing,plastically stretching, and/or elastically elongating. Thus, an“expandable segment” means a location on the stent that enables it toenlarge in diameter, such as when a balloon is inflated within thestent. Examples include weak points which can rupture, thinned areasthat rupture or stretch, accordion-like structures that elongateelastically or plastically, breaks in the stent that are held togetherwith a breakable member such as a suture, weak link, or spot weld, andvarious other means. The term, “expandable segment” thus encompasseseach and every one of these alternatives. For example, U.S. patentapplication Ser. No. 14/136,318, filed Dec. 20, 2013, and U.S. PatentApplication Publication Nos. 2010/0076548 A1 and 2011/0264207 A1disclose various embodiments of expandable valves, the contents of whichare expressly incorporated herein by reference.

FIGS. 1A-1E are perspective and cutaway views of an exemplary prostheticheart valve 20 of the present application oriented around a presumedflow axis 22. The heart valve 20 comprises a plurality of (usuallythree) flexible leaflets 24 supported partly by an undulating wireform26 as well as by a structural stent 28 (FIG. 1E). The combination of thewireform 26 and the structural stent 28 define a support frame for theleaflets 24. The wireform 26 may be formed from a suitably elasticmetal, such as a Co—Cr—Ni alloy (e.g., Elgiloy® alloy), while thestructural stent 28 may be metallic, plastic, or a combination of thetwo. As seen best in FIG. 1B, the support structure of the wireform 26and stent 28 define an undulating periphery of alternating commissures32 and cusps 34 to which the leaflets 24 are secured. As seen in FIG.1D, outer tabs 30 of adjacent leaflets 24 extend between adjacent wiresat the commissures of the wireform 26 and wrap around a portion of thestructural stent 28. This construction, covered with cloth and securedwith sutures, forms the commissures 32 of the valve that project in anoutflow direction along the flow axis 22. Each commissure 32 is locatedintermediate two arcuate cusps 34 that curve toward the inflowdirection. A soft sealing or sewing ring 36 circumscribes an inflow endof the prosthetic heart valve 20 adjacent to and just radially outwardfrom the cusps 34 and may be used to secure the valve to a nativeannulus, such as with sutures. The wireform 26 and structural stent 28are visible in the cutaway views, and are normally covered with apolyester fabric as shown to facilitate assembly and to reduce directblood exposure after implant.

FIG. 1E shows the inner structural stent 28, which in the illustratedembodiment includes an assembly of two concentric annular bands: anouter band 40 surrounding and in contact with an inner band 42. Althoughthe indicators described herein can be utilized in a number of differentprosthetic heart valves, the illustrated structural stent 28 is thatused in a particular line of heart valves; namely, pericardial heartvalves manufactured by Edwards Lifesciences of Irvine, Calif. Forexample, the Perimount® heart valves that utilize pericardial leaflets24 features an inner stent 28 much like that shown in FIG. 1E. Theannular support bands 40, 42 are relatively thin in a radial dimensionas compared to an axial dimension, and have coincident lower edges thatundulate axially up and down around the circumference. The outer band 40exhibits three truncated peaks between three downwardly curved valleys,while the inner band 42 has generally the same shape but also extendsupward at commissure posts 44. The downwardly curved valleys defined onboth bands 40, 42, as seen in FIG. 1E, are typically termed cusps 46.Many commercial prosthetic heart valves include support frames withannular elements and those of skill in the art would understand thatthey could be modified to include the indicators of the presentapplication.

In the exemplary Perimount® valves, the outer band 40 is metallic (suchas Elgiloy® Co—Cr—Ni alloy) and is formed from an elongated strip ofmetal curved to the generally circular shape and having free ends thatare welded together. In contrast, the inner band 42 is formed of abiocompatible polymer such as polyester (PET) or Delrin® polyacetal thatmay be molded, and also may be formed as a strip, circularized, andwelded or bonded closed (not shown). Both the outer and inner bands 40,42 typically feature a series of through holes that register with eachother so that the assembly can be sewn together. The wireform 26 and thecommissure posts 44 of the inner band 42 provide flexibility to thecommissures of the valve, which reduces stress on the bioprostheticmaterial of the leaflets 24. The inflow end or base of the valve 20surrounded by the sewing ring 36, however, comprises the relativelyrigid circular portions of the structural stent 28. The combination ofthe metallic outer and plastic inner bands 40, 42 presents a relativelydimensionally stable circumferential base to the valve, which isbeneficial for typical uses. These same characteristics of thestructural stent 28 that provide good stability for the surgical valveresist post-implant expansion of the valve, however. Consequently, thestructural stent 28 may be modified to facilitate expansion thereof foruse in a valve-in-valve procedure.

The ability of a previously implanted prosthetic heart valve to expandis not always known. Indeed, the procedure is relatively new, andtherefore most implanted valves have not been designed for radialexpansion. Moreover, expandable valves that are now more frequentlyimplanted may not be easily identified by a surgical team considering avalve-in-valve procedure. Although notes of each patient's surgery aretaken at the time of each procedure, poor record-keeping, a lack ofcommunication between doctors and hospitals, patient relocations todifferent states and even countries, the presence of an emergency, andother factors may make those records unavailable to a subsequentsurgical team years later. Indeed, even information as seeminglystraightforward as the size of the previously implanted prosthetic heartvalve may not be readily available, and imaging from outside the bodymay not provide a precise determination of the valve size.

Consequently, the present application provides various solutions foreasily identifying surgical heart valves in terms of size and type. In apreferred embodiment, at least the size of the heart valve is indicatedon a component thereof in a manner that is visible from outside thebody, post-implant. As used herein, “visible” includes the senses of“readable,” “visualizable,” “detectable,” and “interpretable.” Forinstance, FIG. 1E shows a size indicator 50 formed in each of the cusps46 of the outer band 40. The valve-size indicator 50 may be formed bycutting holes or voids through the radiopaque outer band 40 (a negativeor positive image), or by forming a band of non-radiopaque material andadding radiopaque indicators (a positive image). In some examples, allor a part of the indicator is defined by a thinner and/or a thickerregion of the outer band, for example, by cutting or machining a designinto but not through the outer band. The thickness variations areselected to provide a sufficient change in the radiopacity of the bandto permit visualization of the indicator from outside the body. Somealternatives include through openings as well as thickness variations.Various alternative designs and encoding schemes are described below.The size indicator 50 in this example comprises the numeric characters“21” indicating that the valve orifice size is 21 mm. Heart valve sizeshave been standardized for many years into millimeter incrementsstarting at 19 mm and going up to 31 or 33 mm for larger patients. Thepresent application describes valve-size indicators that follow thisconvention, although it should be understood that other sizingconventions may be used and thus the application should not beconsidered limited to these odd-millimeter-size increments. As for theterm, “valve size,” each prosthetic heart valve has a labeled size(e.g., between 19 and 33 mm in 2 mm increments) that denotes the valvesize, and is of a particular valve model, such as a mitral valve of aparticular type, which the valve packaging reflects.

Components within the prosthetic heart valves can also be coded so thatthey indicate whether the valve is expandable or not. It should beunderstood, however, that the valve-size indicators may also be used fornon-expandable valves, as well as those that are capable of post-implantexpansion. Any subsequent valve surgery benefits from knowledge of thesize of the previously-implanted heart valve. Additional information onthe previously-implanted valve, such as the manufacturer and/or model ofthe valve, and the valve's compatibility with other types of valves isalso beneficial and can be encoded on the prosthetic heart valve aswell.

FIGS. 2-4 illustrate the benefits of providing an indicator such asvalve size on the surgical valve. Although different types of indicatorsare contemplated, for simplicity, only valve-size indicators will bedescribed below. It is to be understood, however, that indicators thatprovide identifying information of any kind are part of the inventiondescribed herein. FIG. 2 is a side elevational view of an assembledsurgical valve 60, which could be the exemplary valve 20 shown in FIGS.1A-1E, but also represents a surgical valve without any indicators. Thatis, embodiments of the surgical valve 20 of the present applicationdesirably have size indicators on one or more internal components thatare visible using imaging but not to the naked eye. Of course, this doesnot preclude adding a radiopaque valve-size indicator to the exterior ofthe valve, but certain internal components as described herein arebetter suited for placement of the indicators. For example, integratingthe indicators with structural elements of the valve permits a similarassembly procedure as for a non-indicator valve, as well as maintaininga similar part-count. Incorporating the indicators internally also doesnot materially affect the hemodynamics of the valve. Indeed, avalve-size indicator on the exterior of the valve that is visible to thenaked eye is not precluded either, though such would not necessarilyshow up under imaging, post-implant.

FIG. 3 is a schematic view of an image of a prosthetic heart valve ofthe prior art as seen using an X-ray or other imager from outside thebody in the same orientation as FIG. 2. The X-ray imager identifiesthose components within the heart valve, typically metallic, that blockthe X-ray spectrum radiation. In the embodiment shown, which is asurgical heart valve similar to that described above, the X-ray imagerreveals an internal wireform 62 and a support band 64. Portions thatblock the X-ray beam will show up darker than other portions. The priorart valve of FIG. 3 has no size identifiers thereon, and thus a surgeonviewing the image would need to make an educated guess as to theparticular valve size. Given that valves are produced with orifice sizesin only two millimeter increments, the task is somewhat difficult.

FIG. 4, on the other hand, is a screen shot of an X-ray image of theprosthetic heart valve 20 of FIGS. 1A-1E. Again the X-ray imagerilluminates both the wireform 26 and outer band 40, however thevalve-size indicators 50 also appear. That is, the indicators 50comprise the numeral “21” which have been cut into each of the threecusps 46 of the band 40. Because the indicators 50 are provided at allthree cusps, they is conveniently visible from different orientations. Asurgeon can thus easily identify the valve size, 21 mm, and proceedaccordingly. As will be described below, additional features may beprovided on the radiopaque components of the prosthetic heart valve 20that indicate its expandability and that would show up on an X-ray imageas seen in FIG. 4.

The term “imager” for use from outside the body (“external imager”) todetect the indicators includes any device capable of visualizingdiscrete elements inside the body from the outside, in general anydevice used in the fields of radiology that can produce such images.These fields include X-ray imaging or fluoroscopy which sees reflectedX-rays, magnetic resonance imaging, medical ultrasonography orultrasound, and nuclear medicine functional imaging techniques such aspositron emission tomography. The term “imager” also includes devices orsystems that include at least one component that is disposed within apatient's body, for example, an ultrasound emitter.

As mentioned, various alternatives of the valve-size indicators aredescribed herein. FIGS. 5A-5D are elevational views of outer supportbands for use in the valve of FIGS. 1A-1E with valve-size indicatorsthereon in various locations. FIG. 5A shows the outer band 40 describedabove having the valve-size indicators 50 on all three of the cusps 46thereof. Again, the valve-size indicators 50 comprise the “21” cutthrough the thickness of the metallic band 40 so that its image willshow up in negative on X-ray in contrast with the dark “positive”reflected portions of the rest of the band. It should be noted thatwhile the same indicator, in this case the valve size “21” mm, is shownat all three locations, different indicators can be used as well. Thus,different symbols providing different types of identifying informationcan be provided in the three different locations along the band. Itshould be understood that indicators may be located anywhere along theband and not only at the cusps and/or commissures, and that the band mayinclude any number of indicators.

The outer band 40 comprises two overlapping free ends 66 held togetherby a frictional sleeve 68. This is one possible embodiment permittingexpansion of the band 40, and thus the entire valve 20. More detailabout this arrangement will be provided below. It should be notedhowever that the inner band 42 (FIG. 1E) also preferably includes anexpansion feature at the same location where the outer band expands.Examples of suitable expansion features for the inner band includestructures that expand or are easily ruptured. For example, as shown inFIG. 1E, the inner band 42 features a break point such as a notch 69located at one cusp of 46 of the band structure. The notch 69 representsa reduced cross-sectional area that can be broken or stretched byapplying sufficient outward expansion force from within. For example, aballoon used to expand a secondary prosthetic valve within the surgicalvalve can provide sufficient outward force to cause the inner band 42 torupture or stretch at the notch 69. The material of the inner band 42may be relatively brittle so that excessive tensile forces cause thenotch 69 to break, or the material can be more ductile which permits thenotch 69 to plastically stretch in the manner of taffy.

FIGS. 5B and 5C illustrate alternative outer bands 70, 72, respectively,which have single size indicators 74, 76 thereon. In the former case, asingle size indicator 74 in the form of the numeral “21” is cut into oneof the cusps 76 of the band 70. In the latter instance, the single sizeindicator 77 has been relocated to one of the truncated commissures 78of the band 72. The valve-size indicators 74, 76 may be placed in eitherposition, though slightly more material is available at the commissures78. Furthermore, the size indicator 76 in the band 72 is cut entirelythrough the thickness of the band, and can function simultaneously as asubstitute for the holes or openings 80 that are normally provided atthe commissures to attach the outer band to an inner band with suture.FIG. 5D illustrates a band 82 similar to that shown in FIG. 5C, butwhere there are valve-size indicators 84 at each of the truncatedcommissures 86.

FIG. 6A illustrates a still further example of an outer support band 90having a symbolic valve-size indicator 92 located at one of the cusps94. In this case, the valve-size indicator 92 comprises a pair ofgeometric shapes cut into the band 90 that together indicate the valvesize. FIG. 6B illustrates an exemplary key chart for decoding themeaning of the symbolic valve-size indicator 92 that would be providedalong with the valve, and made available for use by surgeons seeking todecode the indicator, for example, on a webpage or other readilyaccessible location. For example, the first column of the key chartmatches various geometric shapes with single digits, and corresponds toboth the first or left indicator symbol and the digit in the firstposition of the valve size number. Likewise, the second columncorresponds to the second or right indicator symbol and the digit in thesecond position of the valve size number. In the illustrated embodiment,the left indicator symbol is a circle, and the right indicator symbol isa square. Therefore, the digit in the first position of the valve sizenumber corresponding to the circle is 2, and the digit in the secondposition of the valve size number corresponding to the square is 1, sothat the indicated valve size is “21” or 21 mm. Using relatively largeand simple geometric shapes that can be easily distinguished from oneanother upon imaging may be preferable to numeric characters whichsometimes are subject to ambiguity (e.g., distinguishing a “1” from a“7”). Other schemes for encoding information are used in otherembodiments, for example, a palindromic scheme that reads the same ineither direction. In other schemes, the encoding is selected so that astring of characters read backwards is not mapped to the representationfor a different size.

The term “voids” refers to numbers, holes, geometric or other symbolsformed or cut into the radiopaque support bands described herein, orother radiopaque internal elements of a valve support frame. By cuttingthe void into an otherwise solid element, the indicator will show up asa negative image when visualized through an external imager. Forexample, the numeric characters “21” shown in the band 40 of FIG. 5A orthe geometric shapes formed in the band 90 of the FIG. 6A comprise voidsin the otherwise solid outer profile of the bands. Positive images mayalso be generated as well using appropriately shaped cut-outs. Someembodiments use a combination of positive and negative images, forexample, to encode different types of information, and/or tounambiguously differentiate a first digit from a second digit.

FIG. 7 shows another outer support band 96 having a plurality of holes98 formed around its circumference whose number equals the valve size inmillimeters. That is, counting the number of holes or openings 98provides the valve size. In the illustrated embodiment, although not allare shown, there are 23 holes such that the valve sizes 23 mm. Theexisting holes 99 at the commissures for attaching the bands togetherare desirably included in the count to avoid confusion. In any scheme,the openings need not be disposed equidistantly around the band. Forexample, some in some schemes, the positions around the band areassigned hierarchies, each of which is are filled before the next level.For example, in one scheme, the three positions at the commissures arefilled first, followed by positions clockwise of the commissures, etc.,so that the openings are grouped into three sets that can differ by atmost 1 opening. Such a scheme facilitates determination of the precisenumber of openings.

FIG. 8A illustrates a further variation of outer support band 100 havinga symbolic indicator 102 thereon at one of the commissures 104. In thisinstance, patterns of geometric shapes are cut that incorporate one ofthe existing suture holes to represent each size. FIG. 8B is a key chartfor decoding the meaning of the symbolic valve-size indicator 102. Inthe illustrated embodiment, the pattern includes a square and twocircles, which corresponds to 21 mm.

FIG. 9A is a still further outer support band 110 having a symbolicindicator 112 located at one of the commissures 114. In this embodiment,patterns of dots and dashes (similar to Morse code) again incorporatingone of the existing suture holes are used to represent each valve size.FIG. 9B is a key chart for decoding the meaning of the symbolicvalve-size indicator 112. The shapes cut into the commissure 114included a dash and two dots, which corresponds to a size of 21 mm. Theuse of dashes and dots may be easier to decipher rather than trying todiscern the different geometric shapes as in FIG. 8A.

In FIG. 10, an outer support band 120 features a plurality of holes 122provided on one of the cusps whose number symbolizes a particular valvesize. Although not shown, a key chart could be provided to decode thesymbol. However, typically heart valves start at 19 mm and go up by 2 mmincrements, and thus the convention of using one dot for 19, two for 21,etc., may become well-understood. Therefore, the symbol shown, two holes122, corresponds to about size of 21 mm, or the second smallest valvesize. Likewise, three holes would correspond to a valve size of 23 mm,and so on. As discussed above, the hole or openings need not beadjacent, for example, may be distributed and/or grouped for more rapididentification.

FIGS. 11A and 11B show support bands 130, 140, respectively, each havinga single geometric symbol formed in at least one of the cusps thatsymbolizes a particular valve size. In particular, the band 130 in FIG.11A features a symbol 132 in the form of a circle which might indicate avalve size of 19 mm, while the band 132 in FIG. 11B features a symbol134 in the form of the square which might indicate a valve size of 21mm. Again, a key chart might be provided, or the symbols may becomegeneric in the industry such that surgeons will quickly recognize theirmeaning.

FIG. 12 illustrates an outer support band 150 having a radiopaquecoating 152 thereon in a pattern that symbolizes a particular valvesize. In the illustrated embodiment, the coating 152 extends entirelyaround the band 150 except for two gaps 154 that separate a single strip156 from the rest of the coating. The number of gaps 154 indicates thevalve size, in a similar manner to the number of holes 122 provided inthe band 120 of FIG. 10. That is, the two gaps 154 in the illustratedembodiment correspond to a valve size of 21 mm, while a single gap wouldcorrespond to a smaller valve size of 19 mm and three gaps to 23 mm. Inthis embodiment, the material of the band 150 would not be intrinsicallyradiopaque, as opposed to the other bands described which are preferablymetallic. For example, the band 150 might be formed of a relativelyrigid polymer to provide the strength needed, but which does not show upon X-ray.

FIGS. 13A-13C are perspective views of further prosthetic heart valvesupport bands capable of post-implant expansion with indicators thereonfor both size and expansion capability. FIG. 13A shows a support band160 having numerical valve-size indicators 162 at each cusp 164, and oneor more symbols 166 visible using external imaging and indicating thecapability for expansion at each commissure 168. In the illustratedembodiment the symbols 166 comprise a series of three holes thatincorporate the existing suture hole that joins the inner and the outerbands together. This scheme permits a surgeon contemplating areplacement operation to quickly confirm that a valve-in-valve procedureis a possibility, and also confirm the existing implanted valve size.

FIG. 13B shows an outer band 170 having small depressions or concavities172 formed at the peaks of the truncated commissures, which is distinctfrom the regular convex peaks such as those seen at the commissures ofthe bands described elsewhere herein. The concavities 172 indicate thecapacity for valve expansion, post-implant. This alteration takesadvantage of the relatively large surface area of the outer band 170 inthe commissure areas without affecting valve function.

Finally, in FIG. 13C, a support band 180 again has the size indicatorsaround its circumference so as to be readily identifiable in the body,post-implant, by external imaging. In contrast to the band 160, thesupport band 180 features an arcuate upwardly convex slot 182 at eachcommissure. Again, this indicator 182 may be easily visualized usingexternal imaging, and clearly indicates to a surgeon that thisparticular valve is expandable and suitable for a valve-in-valveprocedure.

FIG. 13D shows in detail the interaction between two overlapping freeends 190, 192 located at one cusp of any of the bands described hereinthat slide with respect to one another and permit expansion of thecorresponding heart valve. The free ends 190, 192 are substantiallyrectangular in shape and one resides radially within and against theother. A sleeve 194 surrounds the free ends 190, 192 and holds themradially together. The sleeve 194 desirably comprises polyester (e.g.,PET) shrink wrap tubing, or may be an elastic material, such as siliconerubber, and is shown transparent to illustrate the mating free ends 190,192. The two free ends 190, 192 may slide apart a predetermined distancewhile still being overlapping. The flexible sleeve 194 provides aminimum amount of friction but generally serves to maintain alignment ofthe free ends 190, 192. Each of the free ends 190, 192 further includesa circumferentially-oriented slot 196 that stops short of the terminalends and provides a pathway for fluid flow. The slots 196 extend fartheroutward from the sleeve 194 so that fluid can always enter the spaceswithin the sleeve. During storage, the slots 196 permit flow of a fluidbetween the overlapping free ends 190, 192 to allow for sterilization.With regard to break strength, the sleeve configuration in FIG. 13A-13Bmay require an average breaking pressure of about 1.2 atm, and within arange of from about 0.5 atm to about 2.0 atm. Further, the sleeve 194may be biodegradable to maintain alignment of the two free ends 190, 192for a period after implant and to then degrade to permit easy expansionof the band.

It should be noted here that the valve-type indicator, described hereinas identifying an expandable valve, can also be used to provide furthervalve type information. For instance, the indicator may show what typeof bioprosthetic tissue or other material is used in the valve, thevalve manufacturer and/or model, the valve's compatibility with othervalves, etc. Consequently, the term “valve type” refers to anyvalve-specific information, not just whether the valve is capable ofexpansion.

FIG. 14A is a perspective view of an inner core member 200 of anexemplary sewing ring for use in a heart valve as described herein withstrips of radiopaque material 202 shown exploded above that can beincorporated into the sewing ring to indicate valve size. In theillustrated embodiment, the strips of radiopaque material 202 areprovided in a single elongated strip 204, and two relatively shortstrips 206. By assembling these strips 204, 206 against the core member200, which is typically covered with a biocompatible fabric prior toassembly with the rest of the heart valve, they can be visualized usingexternal imaging to indicate the valve size. For example, FIG. 14B is aschematic top view as seen using an X-ray or other imager from outsidethe body of the valve having the radiopaque strips 204, 206 as indicatedin FIG. 14A. The strips 204, 206 show up dark surrounding the similarlydark metallic components of the valve (annular), and can be interpretedto determine the valve size. For instance, the two short strips 206create three gaps 208 around the sewing ring which might represent avalve size of 23 mm (one gap equals 19 mm, two gaps equal 21 mm, etc.).Alternatively, radiopaque beads can be used as indicators. Thisembodiment represents numerous other ways in which the valve size can becoded into the valve using any of the internal valve components, whetherintrinsically radiopaque or not. Some embodiments use a combination ofradiopaque strips or beads in the sewing ring and cutouts in the band,which permits encoding additional information and/or redundant encodingof more important information.

FIGS. 15A-15C illustrate a further surgical prosthetic heart valve 220of the present application having an expandable lower frame 222 withvalve-type indicators 224 disposed thereon. The heart valve 220 includesan upper valve portion 226 connected to the lower frame 222. Thevalve-type indicators 224 may be on the upper valve portion 226 or lowerframe 222, or both. In a preferred embodiment, the heart valve 220 andthe frame 222 are capable of expansion to enable a valve-in-valveprocedure as described elsewhere herein. The lower frame 222 is designedto expand during the original implant of the valve 220, while both thevalve portion 226 and the frame 222 expand during a subsequentvalve-in-valve procedure. That is, the upper valve portion 226 is notintended to expand and functions much like a typicalnon-collapsible/non-expandable surgical valve during original implantand functioning, but include features that permit a limited amount ofexpansion when subjected to large radial, outward forces from within,such as from expanding a balloon. The lower frame 222 may be made of aplastically-expandable material such as stainless steel orcobalt-chromium alloy, or a self-expandable material such as nitinol.

The upper valve portion 226 desirably includes a peripheral internalsupport frame, partially shown in the cutaway of FIG. 15B, which definesthree upstanding commissure posts 230 alternating with three arcuatecusps 232. The commissure posts 230 project in an outflow direction andsupport outer edges of three flexible leaflets 234, shown in FIG. 15Bbut removed in FIG. 15A for clarity. The leaflets 234 are desirablyseparate bioprosthetic leaflets; for instance being cut from sheets oftreated bovine pericardium, and each features an arcuate cusp edge thatattaches along one of the arcuate cusps of the support frame, and twocommissure edges or tabs that attach up adjacent commissure posts 230. Afree edge 236 of each leaflet is suspended between the adjacentcommissure posts 230 and comes into contact, or coapts, with the freeedges of the other leaflets in the flow orifice defined within theperipheral support frame to form the one-way flow valve.

In a preferred embodiment, the support frame is defined partly by anundulating wireform 240 that defines the commissure posts 230 andextends around a generally tubular area and a structural stent 242 thatmay comprise annular bands; the parts similar to those shown at 62 and64 in FIG. 3. The wireform 240 may be formed from a suitably elasticmetal, such as a Co—Cr—Ni alloy, for example, Elgiloy® alloy, while thestructural stent 242 may be metallic, plastic, or a combination of thetwo. As seen in FIG. 15B, outer tabs 244 of adjacent leaflets 234 extendunderneath the wireform 240 and wrap around a portion of the structuralstent 242 at the commissure posts 230. A soft sealing or sewing ring 246circumscribes an inflow end of the prosthetic heart valve 130 and istypically used to secure the valve to a native annulus such as withsutures. The wireform 240 and structural stent 242 of the support frameare partially visible in the cutaway of FIG. 15B, and are normallycovered with a polyester fabric 248 to facilitate assembly and to reducedirect blood exposure after implant.

The prosthetic heart valve 220 is considered a “hybrid” type in that itincludes the upper valve portion 226 constructed similar to typicalsurgical valves, with a relatively stable diameter that is not normallyintended to be compressed or expanded, while the connected lower frame222 is expandable to help in anchoring the valve in place. One specificcommercial prosthetic heart valve that is constructed in this manner isone which is sold in conjunction with the Edwards Intuity® valve systemfrom Edwards Lifesciences of Irvine, Calif. The Edwards Intuity® valvesystem comprises a “hybrid” valve incorporating a surgicalPerimount®-like valve with a stainless steel lower frame structure. Incontrast to a typical Edwards Intuity® valve, however, the valve portion226 is modified in any of the manners described herein to permitpost-implant expansion for use in a valve-in-valve procedure. Further,the heart valve 220 includes a size indicator to facilitate such aprocedure.

With specific reference to FIG. 16, which illustrates the lower frame222 in perspective, the lower frame 222 includes a plurality ofcircumferential row struts connected by a series of spaced axial columnstruts. Specifically, an upper or outflow row strut 250 extendscontinuously around a periphery of the frame 222, and preferably followsa gently undulating path so as to match a similar shape of the undersideof the upper valve portion 226. As seen in FIG. 15C, three peaks 251along the upper row strut 250 correspond to the locations of thecommissures 230 of the valve 220, where the stent 242 rises upward aswell. In general, the lower frame 222 attaches to an inflow end of theupper valve portion 226, and preferably directly to the internal supportframe or to fabric covering the internal support frame. The lower frame222 is generally tubular in the drawings, and on deployment, expands tobe somewhat frustoconical with the free end farthest from the uppervalve portion 226 expanding outward but the end closest remaining aboutthe same diameter. Optionally, the lower frame is pre-crimped into agenerally conical shape with the free end having a smaller diameter thanthe upper row strut 250, which is not substantially radially compressed.

The upper row strut 250 includes a plurality of eyeholes 252, evenlyspaced apart in the illustrated embodiment, and located just below thetop edge thereof that are useful for securing the frame 222 to thefabric of the underside of the valve portion 226, for example, usingsuture. A series of axial column struts 254 depend downward from theupper row strut 250, and specifically from each of the eyeholes 252, andconnect the upper row strut to two lower row struts 256. The lower rowstruts 256 circumscribe the frame 222 in zig-zag patterns, with aninverted “V” shape between each two adjacent column struts 254. Thelower row struts 256 preferably extend horizontally, and the length ofthe column struts 254 thus varies with the undulating upper row strut250.

As mentioned above, the lower frame 222 may be plastically expanded,such as by balloon expansion, and may be formed of stainless steel orcobalt-chromium alloy, for example. In a typical Edwards Intuity® valve,the upper row strut 250 is generally ring-like without capacity forexpansion. In the illustrated frame 222, on the other hand, a series ofspaced notches 260 are provided that permit expansion. That is,circumferential segments of the strut 250 are interrupted by theV-shaped notches 260 which permits a limited amount of expansion, forexample, about 3 mm in diameter, to accommodate a supplementalexpandable valve to be inserted and expanded therein.

In addition, a number of valve-type indicators 224 are integrated intothe frame 222 at locations around its circumference, such as threevalve-size indicators. In the illustrated embodiment, the valve-sizeindicators 224 comprise small plate-like tags inscribed with thenumerical valve size in mm, for example 21 mm in the illustratedembodiment. The use of any combination of alphanumeric characters and/orsymbols that signify size and/or other features of the valve iscontemplated. The frame 222 may be laser cut from a tubular blank, withthe plate-like size indicators 224 left connected to one more of thestruts. As shown, the size indicators 224 are located just below thepeaks 251 of the undulating upper row strut 250, connected between thecorresponding eyehole 252 and the descending column strut 254. There arethus three size indicators 224 spaced about 120° apart around the frame222. The illustrated location beneath the peak 251 provides additionalspace between the upper row strut 250 and the adjacent lower row strut256. Further, the frame 222 typically has more real estate in which toplace the size indicators 224 than the bands of the valve portion 226.The inscribed or cutout valve size numerals are sufficiently large to bevisualized with X-ray, Transesophageal Echocardiogram (TEE), or otherimaging technique. In one embodiment, the valve size numerals are fromabout 1.5 mm to about 2 mm in height, for example, about 1.75 mm.

It should be understood that instead of the numerical valve-sizeindicators cut into the tags, any of the above-referenced sizeindicators may also be used in the same place. It is especially usefulwhere the indicators are integrated into existing structures rather thanbeing separate add-ons that require a separate attachment step. This notonly reduces assembly time and cost, but also ensures the indicators arelocated at the ideal location for visualization, without requiring analignment procedure. For instance, the various indicators disclosedherein are laser cut or stamped into the respective metallic parts, ordistinguished by providing reflective coatings and the like on theparts.

Note that there are many variations of the above-described embodiments,including numerous combinations of the various embodiments, all of whichare in the scope of the invention. For instance, the various numeric andsymbolic indicators of valve size or valve type could be provided asradiopaque additions to the sewing ring, or in general mixed and matchedas deemed necessary. Also, a particular support structure could have anycombination of the above-discussed expandable portions.

As previously described, the at least one size indicator can be made ofany suitable material, e.g., radiopaque or radiopaque impregnatedmaterial. The radiopaque material selected for this purpose may bebiocompatible. Such materials include stainless steel, tungsten,tantalum, platinum, gold, barium silicate, as well as alloys such ascobalt-chromium (e.g., Elgiloy® alloy) or high-performance nickel alloys(e.g., Hastelloy® alloys).

Various processes exist for forming the radiopaque markers from suchmaterials. In some embodiments, an etching process can be used to createthe articles of the markers. This process may be a photo etching processwhereby a photo-resistive coating is applied as a mask to alight-sensitive polymer plate. Light is projected onto the plate and theplates are then washed to remove the photo-resistive material that wasused as the mask. An additional washing step may then be used tochemically remove the portion of the metal that was exposed to thelight. In other embodiments, the photo-resistive coating and the exposedmetal can be removed in one washing step. Other similar etchingprocesses may be used as are known to those skilled in the art.

Another mechanism for creating the radiopaque articles for use in thedescribed markers involves punching the articles from a sheet ofradiopaque material. For instance, a ribbon of material may be fed intoa die set having male and female portions that stamp out the characters.With a punching process, any rough edges and/or burrs generated therebymay need to be removed, polished, or cleaned.

Yet another technique for producing the radiopaque articles involvesusing a laser cutting technique, as mentioned. Laser cutting can producevery tight tolerances and smooth edges, aiding readability of smallradiopaque markers. Some materials, however, may be expensive ordifficult to process using this technique. In particular, this techniquemay be expensive at higher volume production levels.

Still another option for creating the radiopaque articles involves asintering process. According to this technique, powdered radiopaquematerial mixed with glue is pressed into a form and baked until all ofthe glue has been dissipated and the radiopaque particles bind together.This type of process creates a porous structure which may more readilyadhere to the molecules of a polymer used during a subsequent moldingprocess, with the degree to which the polymer is received by the poresbeing dependent upon molecular size of the polymer.

Metal injection molding can also be used to create the radiopaquearticles. In this scenario, a radiopaque powder or slurry is injectedunder pressure into a mold. The powder or slurry is then baked until theradiopaque particles bind one to another. As with sintering, this mayproduce a relatively more porous radiopaque article.

A prosthetic valve may lose effectiveness or fail for any number ofreasons, for example, stenosis, pannus growth, regurgitation, and/ormechanical failure. Under such circumstances, replacement may bedesirable. One option is to remove the failing prosthetic valve, forexample, surgically, and to implant a new prosthetic valve in its place,Another option is to perform what-is-known as a valve-in-valve procedurein which a new valve is implanted into the failing valve without removalthereof. Where the new valve is a transcatheter valve, the procedure maybe performed using minimally invasive procedures that are less traumaticto the patient. Although the failing valve is not actually removed, theprocedure is often referred to as a “replacement” because the newprosthetic valve replaces the function of the failing valve.

An embodiment of a method for replacing a first prosthetic valve in needthereof with a second prosthetic valve includes reading a valve-typeindicator of the first prosthetic valve, selecting a second prostheticvalve based on the information read, and deploying the second prostheticvalve in the first prosthetic valve. The first prosthetic valve includesany prosthetic valve including a valve-type indicator, including any ofthe embodiments described herein. The valve-type indicator can be of anytype or combination of types described herein, for example, size,expandability, make, model, or any other information desired. Thevalve-type indicator is read, imaged, or visualized as described above.

Optionally, a diameter of the first prosthetic valve is expanded, forexample, either immediately before, contemporaneously with, orsimultaneously with the deployment with the second prosthetic valve. Insome examples, the first prosthetic valve is expanded mechanically, forexample, using a balloon, before the second prosthetic valve isdeployed. In other examples, the deployment of second prosthetic valveitself expands the diameter of the first prosthetic valve. In someembodiments, the second prosthetic valve is a transcatheter heart valve,for example, a balloon expandable or self-expandable transcatheter heartvalve. Optionally, the second valve is expanded post-deployment toimprove engagement between the first valve and the second valve.

While the invention has been described with reference to particularembodiments, it will be understood that various changes and additionalvariations may be made and equivalents may be substituted for elementsthereof without departing from the scope of the invention or theinventive concept thereof. In addition, many modifications may be madeto adapt a particular situation or device to the teachings of theinvention without departing from the essential scope thereof. Therefore,it is intended that the invention not be limited to the particularembodiments disclosed herein, but that the invention will include allembodiments falling within the scope of the appended claims.

What is claimed is:
 1. A method of deploying a second prosthetic heartvalve within a first prosthetic heart valve previously implanted in apatient's body, comprising: using an external imager, viewing avalve-type indicator of a first prosthetic heart valve implanted in thepatient, the valve-type indicator signifying the capability of the firstprosthetic heart valve for post-implant expansion; deploying a secondprosthetic heart valve within the first prosthetic heart valve; andexpanding the second prosthetic heart valve within the first prostheticheart valve to cause a diameter of the first prosthetic heart valve toexpand.
 2. The method of claim 1, wherein the valve-type indicatorfurther indicates one of the group selected from: valve size, valvemake, or valve model.
 3. The method of claim 1, wherein the firstprosthetic heart valve has a labeled valve size, and the valve-typeindicator further indicates the labeled valve size.
 4. The method ofclaim 3, wherein the valve-type indicator comprises a numerical valuethat equals the labeled valve size in millimeters.
 5. The method ofclaim 1, wherein the external imager is selected from one of the groupconsisting of: X-ray imaging, fluoroscopy, magnetic resonance imaging,medical ultrasonography or ultrasound, and positron emission tomography.6. The method of claim 1, wherein the first prosthetic heart valve hasan internal support frame defining a flow orifice therethrough, whereinthe internal support frame is adapted for post-implant expansion, andthe first prosthetic heart valve has a plurality of flexible leafletsattached to the support frame and extending across the flow orifice andcoming together within the orifice to define one-way flow therethrough.7. The method of claim 6, wherein the internal support frame comprises astructural component that shows up as a positive image on the externalimager, and the valve-type indicator is formed by one or more voidsintegrated into the structural component which show up as negativeimages on the external imager.
 8. The method of claim 7, wherein thestructural component of the internal support frame comprises a generallytubular band with a diameter that is expandable post-implant.
 9. Themethod of claim 6, wherein the first prosthetic heart valve furtherincludes an expandable tubular frame attached to an inflow end of theinternal support frame on which the valve-type indicator is located. 10.The method of claim 1, wherein the first prosthetic heart valve has asoft sealing ring surrounding an inflow end, and the valve-typeindicator is mounted to the sealing ring.
 11. A method of deploying asecond prosthetic heart valve within a first prosthetic heart valvepreviously implanted in a patient's body, comprising: using an externalimager, viewing a valve-type indicator of a first prosthetic heart valveimplanted in the patient, the first prosthetic heart valve having afirst functional diameter as implanted, the valve-type indicatorsignifying the capability of the first prosthetic heart valve forpost-implant expansion; mechanically expanding the first prostheticheart valve to a larger second non-functional diameter; and deploying asecond prosthetic heart valve within the first prosthetic heart valve.12. The method of claim 11, wherein the valve-type indicator furtherindicates one of the group selected from: valve size, valve make, orvalve model.
 13. The method of claim 11, wherein the first prostheticheart valve has a labeled valve size, and the valve-type indicatorfurther indicates the labeled valve size.
 14. The method of claim 13,wherein the valve-type indicator comprises a numerical value that equalsthe labeled valve size in millimeters.
 15. The method of claim 11,wherein the external imager is selected from one of the group consistingof: X-ray imaging, fluoroscopy, magnetic resonance imaging, medicalultrasonography or ultrasound, and positron emission tomography.
 16. Themethod of claim 11, wherein the first prosthetic heart valve has aninternal support frame defining a flow orifice therethrough, wherein theinternal support frame is adapted for post-implant expansion, and thefirst prosthetic heart valve has a plurality of flexible leafletsattached to the support frame and extending across the flow orifice andcoming together within the orifice to define one-way flow therethrough.17. The method of claim 16, wherein the internal support frame comprisesa structural component that shows up as a positive image on the externalimager, and the valve-type indicator is formed by one or more voidsintegrated into the structural component which show up as negativeimages on the external imager.
 18. The method of claim 17, wherein thestructural component of the internal support frame comprises a generallytubular band with a diameter that is expandable post-implant.
 19. Themethod of claim 16, wherein the first prosthetic heart valve furtherincludes an expandable tubular frame attached to an inflow end of theinternal support frame on which the valve-type indicator is located. 20.The method of claim 11, wherein the first prosthetic heart valve has asoft sealing ring surrounding an inflow end, and the valve-typeindicator is mounted to the sealing ring.
 21. The method of claim 11,wherein the second prosthetic heart valve is expanded post-deployment toimprove engagement between the first prosthetic heart valve and thesecond prosthetic heart valve.
 22. The method of claim 11, wherein thedeployment of the second prosthetic heart valve itself expands thediameter of the first prosthetic heart valve.